Remove problem screenshot in header units walkthrough (#4462)

* Remove problem screenshot, standardize ui

* Choose buttons

* Improve 2nd project procedure

* Add versioning, update location of image

* Update date

Author: colin-home

docs/build/reference/header-unit-json-reference.md

@@ -6,6 +6,7 @@ author: "tylermsft"
 ms.author: "twhitney"
 f1_keywords: ["header-units.json"]
 helpviewer_keywords: ["header-units.json", "header unit"]
+monikerRange: '>=msvc-160'
 ---
 
 # C++ header-units.json reference

docs/build/walkthrough-header-units.md

@@ -6,6 +6,7 @@ ms.custom: "conceptual"
 author: "tylermsft"
 ms.author: "twhitney"
 helpviewer_keywords: ["import", "header unit", "ifc"]
+monikerRange: '>=msvc-160'
 ---
 
 # Walkthrough: Build and import header units in Microsoft Visual C++